The invention provides a method for preparing high-purity chlorosilane. According to the chlorosilane prepared by a reaction of metallurgical-grade silicon with hydrogen chloride, most of boron and phosphorus impurities are removed through coarse rectification, and then remaining extremely small amount of the boron and phosphorus impurities are removed through adsorption; meanwhile, through the match and selection of the types of adsorbents, replacement frequency of the adsorbents is reduced, and low-cost purification of chlorosilane is realized; and in addition, the operation procedure is simplified, so that the method is suitable for industrialization. According to the method, the boron and phosphorus impurities in the chlorosilane can be efficiently removed, rectification programs are reduced, the service life of the adsorbent is prolonged, cost is reduced, and the method is suitable for industrialization.